Geotechnical Properties of Pond Ash Mixed with Cement Kiln Dust and Polypropylene Fiber

Pond ash (PA) and cement kiln dust (CKD) are major dust products from thermal power stations and cement manufacturing industries and pose disposal difficulties. This research work focuses on the geotechnical properties of pond ash mixed with cement dust and polypropylene (PP) fiber. Various experimental tests, including standard Proctor test, California bearing ratio (CBR) test, direct shear test, and triaxial shear tests, were performed. Pond ash was mixed with 10, 15, 20, 25, and 30% of CKD and 0.5, 1, and 1.5% polypropylene fiber. Standard Proctor tests were carried out on various proposed proportions in order to obtain the effective mix. Original pond ash maximum dry density and optimum moisture contents are $1.45\mathrm{g}/{\mathrm{cm}}^3$ and 23%, respectively. The mix of 75% PA, 25% CKD, and 1% PP fiber produced the maximum dry density. The CBR values increased gradually up to 80% for up to 25% CKD and 1% PP fiber. The shear strength parameters were determined using direct shear testing. The shear strength parameters of cohesion ($c$) and angle of internal friction ($\varphi$) obtained for the mix of 75% PA, 25% CKD, and 1% PP fiber were $5\mathrm{kN}/{\mathrm{m}}^2$ and 39.45°. The same composition was tested in triaxial shear tests under consolidated drained conditions, and shear strength parameters varied slightly. The mix of pond ash, cement kiln dust, and PP fiber can be used for highway embankment construction to strengthen its layers, low land area reclamation, as a structural fill in reinforced earth walls, and backfill material for conventional retaining walls.